Optical amplifier technology and wavelength division multiplexing techniques are typically required in telecommunication systems that provide high power transmissions for long distances. The definition of high power and long distances is meaningful only in the context of a particular telecommunication system in which a bit rate, a bit error rate, a multiplexing scheme, and perhaps optical amplifiers are specified. There are additional factors, known to those skilled in the art, which have impacted upon the definition of high power and long distance. However, for most purposes, high power is an optical power greater than about 10 mW. High power systems often suffer from non-linear optical effects, including self-phase modulation, four-wave-mixing, cross-phase modulation, and non-linear scattering processes, all of which can cause degradation of signals in high powered systems. In some applications, optical power levels of 1 mW or less are sensitive to non-linear effects, so non-linear effects may still be an important consideration in low power systems. In addition, other optical fiber attributes, such as attenuation, contribute to the degradation of the signal.
Generally, an optical waveguide fiber having a large effective area (Aeff) reduces signal-degrading non-linear optical effects, including self-phase modulation, four-wave-mixing, cross-phase modulation, and non-linear scattering processes. Increasing the effective area of an optical waveguide fiber, however, typically results in an increase in macrobending- and microbending-induced losses, which attenuate signal transmission through a fiber. The need for low microbending losses become increasingly important over long transmission distances (e.g. 100 km or more) and in systems with large spacing between regenerators, amplifiers, transmitters and/or receivers. It would be desirable to develop an optical fiber having a large effective area (Aeff) with low bending losses.